Cross flow fan

ABSTRACT

A fan for a cross flow fan assembly, including a plurality of elongate fan blades supported in an axial cylindrical pattern about a rotational axis by disk shape fan blade mounting members located adjacent ends of the blades. The fan blades have radial outer end portions defining an outer diameter of the fan, radial inner end portions opposite the radial outer end portions, and curved intermediate portions between the radial outer end portions and the radial inner end portions, respectively. Each of the fan blades is oriented such that the radial outer end is at about a 28° angle to a line tangent to the fan diameter at the outer end portion thereof, and the radial inner end portion is directed radially inwardly directly toward the axis or such that a line tangential to the radial inner end portion will pass through the axis.

TECHNICAL FIELD

This invention relates generally to a fan for a cleaning system of anagricultural combine, and more particularly, to a cross or transverseflow fan which provides a relatively high air flow volume at arelatively lower cost than other known cross flow fans for combinecleaning systems.

BACKGROUND ART

A typical agricultural combine includes a crop header apparatus whichreaps planted grain stalks and then feeds them to a threshing apparatusarranged within a body of the combine. The threshing apparatus functionsto separate grain from material other than grain. The grain fallsthrough openings in the threshing apparatus and is directed to acleaning system also arranged within the combine body.

A typical cleaning system includes oscillating cleaning sieves. Thecleaning sieves are located below the threshing apparatus to receive thegrain and other materials expelled from the threshing apparatus. Theoscillation of the sieves arranges the material in a crop mat or veil ontop of the sieve. By forcing a stream of air upwardly through the sieve,chaff, straw and other lighter material in the crop material mat isseparated from heavier grain, and the chaff, straw and other lightermaterial is directed out through the rear end of the combine by the airflow. The heavier seeds or grain fall through the sieves for collection.

Developments in modern agricultural combines have led to increased powerand output demands, such that cleaning system capacity has been andcontinues to be a limiting factor to performance of the combine. Areadily achieved method of increasing combine efficiency is to increasethe size of the cleaning area and the sieves to spread the crop materialacross a wider area and in a thinner crop mat or veil. However, it hasbeen found that increasing the width of the cleaning area requiresincreasing the width of the combine. Because of the width of fenceopenings and the size of doors of equipment storage buildings and thelike, increasing the width of a combine beyond current limits presentssignificant problems.

Transverse or cross flow blower fans are particularly useful incombination with combine cleaning sections because they conserve spaceand produce a wide stream of air that is directed upwardly toward thecleaning sieves of the cleaning section. Because the fan in anagricultural combine is disposed closer to the ground over which thecombine moves, increasing fan diameter so as to decrease groundclearance would be undesirable.

Thus, what is sought is a cross flow fan construction capable ofproviding increased and enhanced air flow capability required for alarger cleaning system of a combine, but which overcomes many of theproblems and shortcomings set forth above.

SUMMARY OF THE INVENTION

What is disclosed is a fan for a cross flow fan assembly which overcomesmany of the problems and shortcomings set forth above. According to theinvention, the fan includes a plurality of elongate fan blades supportedin an axial cylindrical pattern about a rotational axis by disk shapefan blade mounting members located adjacent ends of the blades. The fanblades have radial outer end portions defining an outer diameter of thefan, radial inner end portions opposite the radial outer end portions,and curved intermediate portions between the radial outer end portionsand the radial inner end portions, respectively. Each of the fan bladesis preferably oriented such that the radial outer end is at about a 28°angle to a line tangent to the fan diameter at the outer end portionthereof, and the radial inner end portion is directed radially inwardlydirectly toward the axis or such that a line tangential to the radialinner end portion will pass through the axis. Also preferably, the fanhas a diameter of about 15.5 inches, 40 blades, and spacing betweenradial outer ends of adjacent ones of the blades of about 2.375 inches.A preferred depth of the blades as measured between the radial outer endportion and the radial inner end portion thereof is about 2.5 inches,and the blade curvature has a radius of about 2 inches. Also preferably,the fan includes two sets or ranks of the fan blades in end-to-endrelation and skewed toward their common ends. The common ends arereceived in and supported by a single fan blade mounting member inalternating relation one to the other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an agricultural combine including a fan for across flow fan assembly according to the invention;

FIG. 2 is an enlarged perspective view of the fan of FIG. 1;

FIG. 3 is an enlarged end view of the fan of FIG. 2, showing fan bladessupported in a fan blade mounting member of the fan;

FIG. 4 is an enlarged fragmentary end view of the fan, illustratingspacing between the fan blades; and

FIG. 5 is an end view of a fan blade of the fan, showing variousparameters thereof.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, in FIG. 1, a representative agriculturalcombine 10 including a cross flow fan 12 constructed and operableaccording to the teachings of the present invention, for directing aflow of air, denoted by the arrows, upwardly through sieves 14 and 16 ofa cleaning system 18, is shown. Cross flow fan 12 is located in a lowerregion of a chassis or frame of combine 10, generally beneath athreshing system 20, and the flow of air is directed toward sieves 14and 16 by guides of sheet metal or other material (not shown) in thewell known manner.

Referring also to FIG. 2, cross flow fan 12 includes a plurality ofelongate fan blades 22 supported and held in an axial cylindrical,skewed pattern about a central rotational axis 24, by a plurality ofaxially spaced disk shape fan blade mounting members 26, supported on anaxially extending shaft 28.

Referring also to FIG. 3, each fan blade mounting member 26 ispreferably of molded construction of metal or plastics material, andincludes a plurality of curve shape axially facing fan blade mountinggrooves 30 therein at angularly spaced locations around axis 24. Eachmounting groove 30 is adapted for receiving a fan blade 22 therein andincludes a detent tab 32 receivable in a hole (not shown) in a fan blade22 inserted into groove 30, for retaining the blade therein. Mountingmember 26 in FIG. 3 is shown including fan blades 22 mounted inalternating ones of mounting grooves 30, which is representative of thefour fan blade mounting members 26 closest to the axial ends of fan 12.Fan blade mounting member 26 at the middle of fan 12 is different, inthat each of mounting grooves 30 supports a fan blade 22, alternatingones of grooves 30 of that mounting member holding fan blades extendingin opposite axial directions, as best shown in FIG. 2. Fan 12 thusincludes two sets or ranks of fan blades in end-to-end relation, thecommon ends being supported by a single mounting member 26. As alsoshown in FIG. 2, fan 12 preferably has an overall diameter D as measuredaround radial outer end portions 34 of blades 22 of between about 15 and16 inches, as denoted by diameter D in FIG. 2.

Referring also to FIGS. 4 and 5, the radial outer end portions ofadjacent ones of fan blades 22 are preferably spaced apart by betweenabout 2.3 and 2.4 inches, as denoted by distance A in FIG. 4, and radialinner end portions 36 are preferably spaced apart by between about 1.6and 1.7 inches, as denoted by distance B. Referring more particularly toFIG. 5, each individual blade 22 has a preferred overall width asmeasured between end portions 34 and 36 of between about 2.5 and 2.6inches, as denoted at W, and a radius of curvature of between about 2.0and 2.1 inches, as denoted by radius R. Further preferably, a linetangent to radial outer end portion 34 of each fan blade 22 is orientedat about a 28° degree angle to a line tangent to the outer diameter ofthe fan at radial outer end portion 34, as denoted by angle C, and aline tangential to radial inner end portion 36 will pass through axis24, as denoted by line E.

As a result of the above geometrical and dimensional parameters, fanoutput air volume and pressure are significantly increased withoutincreasing fan rotational speed, compared to previously used fans. Thisallows the cleaning system capacity to be increased, without increasingthe size thereof.

It will be understood that changes in the details, materials, steps, andarrangements of parts which have been described and illustrated toexplain the nature of the invention will occur to and may be made bythose skilled in the art upon a reading of this disclosure within theprinciples and scope of the invention. The foregoing descriptionillustrates the preferred embodiment of the invention; however,concepts, as based upon the description, may be employed in otherembodiments without departing from the scope of the invention.Accordingly, the following claims are intended to protect the inventionbroadly as well as in the specific form shown.

1. A cross flow fan for a cleaning system of an agricultural combine,comprising: a plurality of elongate fan blades supported in an axialcylindrical pattern about a rotational axis of the fan by disk shape fanblade mounting members located adjacent axial ends of the blades androtatable about the axis, the fan blades having radial outer endportions defining an outer diameter of the fan, radial inner endportions opposite the radial outer end portions, and curved intermediateportions between the radial end portions, respectively; wherein each ofthe fan blades is oriented such that the radial outer end portion is atabout a 28° angle to a line tangent to the fan diameter at the radialouter end portion and the radial inner end is directed radially inwardlydirectly toward the axis.
 2. The cross flow fan of claim 1, wherein theradial outer end portions of adjacent ones of the fan blades are spacedapart by between about 2.3 and 2.4 inches.
 3. The cross flow fan ofclaim 2, wherein the radial inner end portions of the adjacent ones ofthe fan blades are spaced apart by between about 1.6 and 1.7 inches. 4.The cross flow fan of claim 3, wherein each fan blade has an overallwidth as measured between the radial end portions thereof of betweenabout 2.5 and 2.6 inches.
 5. The cross flow fan of claim 4, wherein thecurved intermediate portion of each of the fan blades has a radius ofcurvature of between about 2.0 and 2.1 inches.
 6. The cross flow fan ofclaim 1, wherein the disk shape fan blade mounting members each includeaxially facing curved grooves for receiving and holding longitudinalends of the fan blades, at least the grooves of a center one of themounting members being adapted for receiving and holding alternatingones of the blades extending in opposite directions.
 7. A cross flow fanfor an agricultural combine for generating and directing a flow of airto a cleaning system of the combine, comprising: a plurality of elongatefan blades supported in an axial cylindrical pattern about a rotationalaxis by disk shape fan blade mounting members located adjacent axialends of the blades and rotatable about the axis, each of the fan bladeshaving a radial outer end portion defining an outer diameter of the fan,a radial inner end portion opposite the radial outer end portion, and acurved shape extending between the radial end portions; wherein each ofthe fan blades is oriented such that the radial outer end portion isoriented at about a 28° angle to a line tangent to the fan diameter atthe radial outer end portion and the radial inner end portion isoriented such that a line tangent thereto will pass through the axis. 8.The cross flow fan of claim 7, wherein the radial outer end portions ofadjacent ones of the fan blades are spaced apart by between about 2.3and 2.4 inches.
 9. The cross flow fan of claim 8, wherein the radialinner end portions of the adjacent ones of the fan blades are spacedapart by between about 1.6 and 1.7 inches.
 10. The cross flow fan ofclaim 7, wherein each fan blade has an overall width as measured betweenthe radial end portions thereof of between about 2.5 and 2.6 inches. 11.The cross flow fan of claim 7, wherein the curve shape of each of thefan blades has a radius of curvature of between about 2.0 and 2.1inches.
 12. The cross flow fan of claim 7, wherein the disk shape fanblade mounting members each include axially facing curved grooves forreceiving and holding longitudinal ends of the fan blades, at least thegrooves of a center one of the mounting members being adapted forreceiving and holding alternating ones of the blades extending inopposite directions.
 13. The cross flow fan of claim 7, wherein the fanhas a diameter of from about 15 to about 16 inches.
 14. A cross flow fanfor an agricultural combine for generating and directing a flow of airto a cleaning system of the combine, comprising: a plurality of elongatefan blades supported in an axial cylindrical pattern about a rotationalaxis by disk shape fan blade mounting members located adjacent axialends of the blades and rotatable about the axis, each of the fan bladeshaving a radial outer end portion defining an outer diameter of the fan,a radial inner end portion opposite the radial outer end portion, and acurved shape extending between the radial end portions; wherein the fanhas a diametrical extent of from about 15 to about 16 inches and each ofthe fan blades is oriented such that the radial outer end portion isoriented at about a 28° angle to a line tangent to the fan diameter atthe radial outer end portion and the radial inner end portion isoriented such that a line tangent thereto will pass through the axis.15. The cross flow fan of claim 14, wherein the radial outer endportions of adjacent ones of the fan blades are spaced apart by betweenabout 2.3 and 2.4 inches.
 16. The cross flow fan of claim 15, whereinthe radial inner end portions of the adjacent ones of the fan blades arespaced apart by between about 1.6 and 1.7 inches.
 17. The cross flow fanof claim 14, wherein each fan blade has an overall width as measuredbetween the radial end portions thereof of between about 2.5 and 2.6inches.
 18. The cross flow fan of claim 14, wherein the curve shape ofeach of the fan blades has a radius of curvature of between about 2.0and 2.1 inches.
 19. The cross flow fan of claim 14, wherein the diskshape fan blade mounting members each include axially facing curvedgrooves for receiving and holding longitudinal ends of the fan blades,at least the grooves of a center one of the mounting members beingadapted for receiving and holding alternating ones of the bladesextending in opposite directions.